Simply put, you gain insight and reach the "dukkha nanas" (orthe ugly stages on the path). Then, the only way to get out of these stages is to gain more insight and progress to the next stage, "equanimity".
This is why Daniel says "the only way to cure insight disease is more insight.
It's not really a disease, and it's not really something you should worry about at all. It's just the natural progression, like going through puberty

-d